In the period straddling the nineteenth and twentieth centuries the most significant bases of the fundamental framework of modern economic theory were extended and studied in depth. A significant number of Italian economists and thinkers furnished contributions of great originality to these foundations, so much so that talk of an Italian school of economics and finance is wholly justified. Since the second half of the nineteenth century, this school has produced contributions of great importance which undoubtedly include some of the most significant milestones of economic theory, extremely stimulating and relevant even today. For most of these works, however, their publication in Italian only was a serious impediment to their dissemination in the broader European and international context. Hence we believe it of considerable interest to collect some of those contributions and publish them in English. This is the third volume in a set of three.